1. Field of the Invention
This invention relates generally to novel semiconductor materials. More specifically, the invention relates to oxychalcogenide crystal compositions.
2. Brief Description of the Prior Art
There exists many more reported crystal structures of tellurates/tellurites containing cationic Te3+/4+, than for oxytellurides containing anionic Te2−. Yet, semiconducting oxytelluride systems may have promise in the field of commercialized optoelectronic applications like transparent semiconductors. The complex orbital hybridizations in anion-ordered multinary crystals like oxytellurides can give rise to unique physical properties. These systems are the cutting edge of applied semiconductor technology research, but further exploration for better suited materials could result in more efficient and/or more effective functional materials. in such a raw materials intensive market, though, a semiconductor that is comprised of the most abundant and/or inexpensive elements may be of the greatest commercial interest and have the most potential for large scale applications.
The copper-based oxychalcogenides (Liu 2007, Zakutayev 2010; Ueda, et al., Thin Solid Films 496 (2006) 8-15; Ohta, et al., Solid-State Electronics 47 (2003) 2261-2267), such as LaCuOX (X═S, Se) and La2O2CdSe2, are classes of materials which may have commercial applications. (Ueda, et al., Applied Physics Letters 77 (2000) 2701-2703; Huang, et al., Journal of Solid State Chemistry 155 (2000) 366-371; Kamioka, et al., Journal of Luminescence 112 (2005) 66-70; Ramasubramanian, et al., Journal of Applied Physics 106 (2009) 6). Transition metal oxysulfides like Sm2Ti2S2O5 have also been identified as stable catalysts for photo-oxidation and reduction of water. (Ishikawa, et al., Journal of the American Chemical Society 124 (2002) 13547-13553; Meignen, et al., Journal of Solid State Chemistry 178 (2005) 1637-1643).